The present invention relates to voiced communication systems and in particular to a ground-to-air communication system, whereby FSK encoded messages can be transmitted over a voiced radio band and from which transmissions the encoded messages can be decoded to produce voiced messages.
A major problem in most air traffic control centers is that over the years, as the amount of air traffic has increased, it has become more and more difficult for a ground controller to monitor each and every aircraft and keep the individual aircraft advised of their relative positions with respect to other aircraft within an area of space. While the individual aircraft are monitored by systems such as the Sperry Univac.RTM. Automatic VFR Advisory Service (AVAS) which employs the Automated Radar Tracking System (ARTS III) it becomes very difficult, due to the limited time bandwidth of the controller's radio channel, to communicate collision-avoidance messages to all pilots. This problem is especially critical during periods of high traffic density and during which periods traffic-warning messages are occasionally lost or delayed due to radio channel saturation. From the standpoint of air traffic safety, it is therefore highly desirable if the AVAS system were also able to automatically advise each pilot independent of controller action as well as to be able to transmit more messages in any given period of time. Such an improved system would also reduce the ground controllers workload, conserve radio channel use and increase the maneuvering time available to aircraft.
It is therefore a primary object of the present invention to transmit digital messages, via FSK encoded analog signals over a ground controller's voice radio band, to an identified aircraft and to decode the message and produce a voiced traffic warning to a pilot over his head set.
It is also an object of the present invention to accomplish the former objective using readily available circuitry but configuring the same in a system that has a vocabulary sufficient to accommodate the majority of the traffic-warning messages which might typically be transmitted from a ground controller.
It is a further object of the present invention to produce a system which is compatible with the Discrete Address Beacon System/Army Tactical Airspace Regulation System (DABS/ATARS) or with the Air Traffic Control Radar Beacon System (ATCRBS). Thus permitting the transmissions of alerts, warnings and resolutions in automatic or semi-automatic fashion.
These objects and others will become more apparent upon a reading of the hereinafter described appartus.